Method for operating a ware washer and ware washer

ABSTRACT

A ware washer, which is designed as a programmable machine or as a conveyor ware washer, has at least one pump, at least one line system connected to the pump, and at least one nozzle system connected to the line system and having at least one nozzle, a liquid being supplied at least intermittently to the at least one nozzle via the line system. A sensor device connected to a control device is provided for detecting a profile of the volumetric flow rate of the liquid in the line system and for comparing the detected flow rate profile with a predetermined flow rate profile. The control device is designed, in the event of a deviation of the detected flow rate profile from the predetermined flow rate profile, automatically either to carry out a regulating action on the operation of the ware washer as a function of the size and the time gradient of a difference between the predetermined flow rate profile and the detected flow rate profile or to issue a fault warning via an optical and/or acoustic interface or to issue a fault warning to a remote maintenance station via a remote control interface.

TECHNICAL FIELD

The invention relates to a method for operating a ware washer and to aware washer, in particular commercial dishwasher or utensil ware washer,which is designed as a programmable machine or as a conveyor warewasher.

The invention is aimed particularly at a method for operating a warewasher which is designed as a programmable machine or as a conveyor warewasher and which has at least one pump, a line system connected to thepump and at least one nozzle connected to the line system, wherein aliquid is supplied at least intermittently to the at least one nozzlevia the line system while the ware washer is in operation.

Furthermore, the invention relates to a ware washer which is designed asa programmable machine or as a conveyor ware washer and which has atleast one pump, a line system connected to the pump and at least onenozzle connected to the line system, wherein liquid is supplied at leastintermittently to the at least one nozzle via the line system.

BACKGROUND

Programmable machines are manually loadable and unloadable ware washers.The programmable machines (called “box-type ware washers” or else “batchdish washers”) may be rack-type push-through ware washers, also calledhood ware washers (“hood-type ware washers”), or front loaders (“frontloader ware washers”). Front loaders may be built-under machines (“undercounter machines”), table top machines (“top counter machines”) orfree-standing ware washers with front loading (“free standing frontloaders”).

A ware washer designed as a programmable machine usually has a treatmentchamber for the cleaning of wash ware. As a rule, beneath the treatmentchamber, a washing tank is arranged, in which liquid can flow out of thetreatment chamber as a result of gravity. Located in the washing tank iswashing liquid which is usually water, to which, if appropriate,detergent can be supplied.

Furthermore, a ware washer designed as a programmable machine has awashing system with a washing pump and with a line system connected tothe washing pump and having washing nozzles. The washing liquid locatedin the washing tank can be conveyed from the washing pump to the washingnozzles via the line system and sprayed through the washing nozzles inthe treatment chamber onto the wash ware to be cleaned. The sprayedwashing liquid subsequently flows back into the washing tank.

Conveyor ware washers are, in particular, belt-type conveyor warewashers (“flight-type ware washers”) or rack-type conveyor ware washers(“rack conveyor ware washer”). Conveyor ware washers are usuallyemployed in the commercial sector.

In contrast to programmable machines in which the wash ware to becleaned remains at a fixed location in the machine during cleaning, inconveyor ware washers a transport of the wash ware through varioustreatment zones of the conveyor ware washer takes place.

A conveyor ware washer usually has at least one prewashing zone and atleast one main washing zone which is arranged downstream of theprewashing zone or prewashing zones, as seen in the direction oftransport of the wash ware. As a rule, at least one postwashing zone andat least one final rinse zone following the postwashing zone orpostwashing zones are arranged downstream of the main washing zone ormain washing zones, as seen in the direction of transport. As seen inthe direction of transport, either the wash ware received directly onthe conveyor belt or the wash ware held by racks usually runs in thedirection of transport through an entry tunnel, the following prewashingzone or prewashing zones, main washing zone or main washing zones,postwashing zone or postwashing zones, final rinse zone or final rinsezones and a drying zone into an exit section.

Said washing zones of the conveyor ware washer are assigned in each casea washing system which has a washing pump and a line system (washingline system) which is connected to the washing pump and via which liquidis supplied to the spray nozzles of the washing zone. The washing liquidsupplied to the spray nozzles is sprayed in the respective washing zoneonto the wash ware which is transported by a transport device of theconveyor ware washer through the respective washing zones. Each washingzone is assigned a tank in which sprayed liquid is received and/or inwhich liquid for the spray nozzles of the respective zones is provided.

In the conveyor ware washers conventionally known from the prior art,final rinse liquid in the form of fresh water, which may be pure ormixed with further additives, such as, for example, rinsing agent, issprayed onto the wash ware via the spray nozzles of the final rinsezone. At least part of the sprayed final rinse liquid is transportedfrom zone to zone, opposite to the direction of transport of the washware, via a cascade system.

The sprayed final rinse liquid is captured in a tank (postwashing tank)of the postwashing zone, from which tank it is conveyed, via the washingpump of the washing system belonging to the postwashing zone, to thespray nozzles (postwashing nozzles) of the postwashing zone. Washingliquid is rinsed off from the wash ware in the postwashing zone. Theliquid which in this case occurs flows into the washing tank of the atleast one main washing zone which precedes the postwashing zone, as seenin the direction of transport of the wash ware. Here, the liquid isusually provided with a detergent and sprayed onto the wash ware via thenozzles (washing nozzles) of the main washing zone by means of a pumpsystem (washing pump) belonging to the washing system of the mainwashing zone. In so far as no further main washing zone is provided, theliquid subsequently flows from the washing tank of the main washing zoneinto the prewashing tank of the prewashing zone. The liquid in theprewashing tank is sprayed onto the wash ware via the prewashing nozzlesof the prewashing zone by means of a pump system belonging to thewashing system of the prewashing zone, in order to remove coarseimpurities from the wash ware.

Conventionally, ware washers are equipped with rinsing pumps whichsupply the line system of the final rinse zone with the final rinseliquid to be sprayed. This ensures, in particular, a virtually constantvolume flow of the final rinse liquid in the final rinse zone. It isalso conceivable, however, to utilize the on-site line pressure, forexample the pressure of the fresh water supply, in order to deliver thefinal rinse liquid to the line system of the final rinse zone. In thislast-mentioned instance, an activatable valve may be provided betweenthe line system and the spray nozzles of the final rinse zone, so that atemporary or complete interruption in the supply of final rinse liquidto the spray nozzles can be achieved.

Irrespective of whether the ware washer is designed as a programmablemachine or as a conveyor ware washer, commercial ware washers thereforeusually comprise at least one pump and/or a valve which ensure/ensures avirtually constant volume flow of the washing liquid or final rinseliquid for the duration of a washing or final rinse process in thetreatment chamber (in the case of programmable machines) or in therespective treatment zone (in the case of conveyor ware washers). Therespective pumps and/or valves on the line system are switched on andoff by means of a control device (machine control) belonging to the warewasher.

However, various operating states of the ware washer, operating errors,insufficient cleaning of the systems or an incorrect installation ofwashing or final rinse arms (for example, after the cleaning of these)may lead to a deviation in the defined water circulation capacity (flowrate) or to a deviation in the desired washing pressure or desiredrinsing pressure or desired nozzle pressure and, consequently, to achange in the washing performance.

The desired washing pressure of commercial ware washers lies in a rangeof approximately 0.1 to 0.8 bar, depending on the type of machine andits size. The desired final rinse pressure of commercial ware washers islikewise dependent on the type and size of the machine, but usually liesin a range of 0.2 to 0.8 bar. The washing liquid volume flow incommercial built-under machines is approximately 100 to 200 l/min, andin belt-type conveyor ware washers is approximately 400 to 800 l/min.The circulated washing liquid volume flows of hood-type and rack-typeconveyor ware washers are between these. In what are known as commercial“Batch Type Dishwasher” machines or programmable machines, a final rinsewater quantity of approximately 1.5 to 3.5 l per cycle is consumed. Incontinuous final rinse processes, as, for example, in conveyor warewashers, the volume flow of the final rinse liquid is approximately 2 to8 l/min.

The publication EP 1 278 449 B1 relates to a domestic ware washer whichhas a washing system with an intermittently activated circulation pumpand with two rotating spray arms. Furthermore, to detect a fluidpressure prevailing at the pump inlet, a sensor device is provided whichis connected to a control device of the ware washer and optionally to anindicator. By the fluid pressure prevailing at the pump inlet beingdetected, it can be ascertained whether the spray arms of the warewasher are functioning properly. In particular, it can be ascertainedwhether the free rotatability of the spray arms is blocked, on accountof pieces of crockery in the treatment chamber. If such an instanceoccurs, the intermittent operation of the circulation pump is changedcorrespondingly so that a predetermined washing result can be achieved.

The publication WO 2004/096006 A2 relates to a ware washer with awashing liquid circuit which is provided with a pressure sensor. It ispossible via the pressure sensor to detect whether the hydrostaticpressure of the washing liquid circulating in the washing liquid circuitundershoots a prefixed threshold value. This occurs, for example, when afilter provided in the washing liquid circuit becomes clogged. In suchan instance, there is the risk that the wash ware to be cleaned is nottreated sufficiently. In order to counteract this, it is proposed toequip the ware washer with an additional washing liquid circuit which iscut in, as required, so that the washing liquid can ultimately besprayed onto the wash ware with a predetermined desired nozzle pressure.

A method for operating a circulation pump in a program-controlled warewasher is known from the publication DE 197 50 266 A1. The circulationpump is activated intermittently so that pressure fluctuations can beintroduced into the washing liquid in a directed manner. This isintended to promote the water flow at a screen, provided in a washingliquid circuit, with the effect of screen cleaning and dirt discharge.In order to prevent the situation where the deliberately introducedinstability in the pressure profile is reduced on account of a loadingof the washing liquid with foam or on account of the degree ofcontamination of the washing liquid, there is provision for, with theaid of a pressure sensor, detecting the pressure profile in thecirculated washing liquid and, in particular, the absence of pressurefluctuations or of specific measurable pressure peaks. If such aninstance occurs, instability is caused in the pressure profile due to anabrupt reduction in the pump rotational speed.

The publication EP 1 008 324 A1 relates to a method for the cleaning ofwash ware in a ware washer, in which washing liquid in a washing liquidcircuit is sprayed onto a wash ware to be cleaned. In the washing liquidcircuit, a pressure sensor is provided, via which the pressure profileof the pump pressure is detected. By means of the detected pressureprofile, it is determined whether air is unintentionally sucked in bymeans of the circulation pump and is therefore in an unstable hydraulicstate. In such an instance, the circulation pump of the ware washer istemporarily switched off or throttled.

SUMMARY

The set problem on which the present invention is based is to ascertainpotential deviations in the water circulation capacity or potentialdeviations in the flow rate and automatically react correspondingly, inorder to counteract the deviation in the water circulation capacity.

In particular, the invention is to achieve the object of providing aware washer designed as a programmable machine or a conveyor ware washerwhich has a washing system with a washing pump, with a line systemconnected to the washing pump and with washing nozzles, potentialmalfunctions of the ware washer which have or may have an adverseinfluence on the treatment result being ascertained as early aspossible. After potential malfunctions have been ascertained,countermeasures are to be automatically initiated, by means of which adeviation in the defined water circulation capacity or a change in thewashing performance can be compensated as early as possible.

Furthermore, the object of specifying a corresponding method foroperating such a ware washer is to be achieved.

The solution according to the invention is distinguished in thatpotential deviations in the volumetric flow rate are detected, usingsuitable flow sensors, and deviations are communicated via faultwarnings to the customer or to the ware washer operator or via a remotecontrol interface to the manufacturing company or to the competentremote maintenance system or are counteracted by means of a change ofprocess parameters.

A suitable flow sensor is a device for sensing the rate of fluid flow.Typically a flow sensor is the sensing element used in a flow meter, orflow logger, to record the flow rate of fluids. As is true for allsensors, absolute accuracy of a measurement requires a functionality forcalibration. There are various kinds of flow sensors and flow meters,including some that have a vane that is pushed by the fluid, and candrive a rotary potentiometer, or similar device.

In this case, the invention is based on the recognition that, in asituation where the desired flow rate in the line system is overshotimmediately after a pump is switched on, this points to a leak in theline system. By contrast, a high overshooting of the desired flow rateis an indication of a faulty installation of the washing or final rinsearms. If the flow rate lies below the desired flow rate, this is anindicator of blockages in the lines or nozzles.

In particular, according to the invention, there is provision, with theaid of a flow sensor, for detecting the profile of the flow rate of theliquid in the line system and comparing it with a predetermined flowrate profile (the ideal desired flow rate profile, in the fault-freeoperation of the machine). If there is a deviation in the detected flowrate profile from the predetermined ideal flow rate profile, at leastone of the following steps is selected and executed automatically as afunction of the type of deviation:

-   -   i) a regulating action is carried out on the operation of the        ware washer; and/or    -   ii) a fault warning is issued via an optical and/or acoustic        interface of the ware washer; and/or    -   iii) a warning is issued to a remote maintenance station via a        remote control interface of the ware washer.

The type of deviation of the detected flow rate profile from thepredetermined (ideal) flow rate profile is determined, in particular, bythe answers to the following questions:

-   -   i) does the detected flow rate profile lie below or above the        ideal flow rate profile?    -   ii) does the deviation in the detected flow rate profile from        the predetermined (ideal) flow rate profile decrease over time        or does it remain constant?    -   iii) does the deviation occur only during continuous operation        or is a deviation present even at the commencement of the        operation of the ware washer?

In the solution according to the invention, therefore, first the type ofdeviation of the detected flow rate profile from the predetermined(ideal) flow rate profile is determined. Thus, a conclusion as to thecause of the deviation of the detected flow rate profile from thepredetermined (ideal) flow rate profile and therefore a conclusion as tothe cause of the deviation can be drawn. It is subsequently establishedwhether the deviation, detected via the flow rate profile, may lead to achange in the washing or final rinse performance of the ware washer.Should this be the case, a check is made as to whether there is apossibility of carrying out a regulating action on the operation of theware washer, so that the potential change in the washing or final rinseperformance can be compensated.

Simultaneously with or alternatively to this, as a function of thedetermined cause of the deviation from the defined water circulationcapacity and from in the defined desired flow rate respectively, anoptical and/or acoustic fault warning is issued to the machine operator,so that the latter can undertake corresponding measures. This is thecase particularly when an operating error is the cause of the deviationfrom the defined water circulation capacity.

If, by contrast, it is determined that the assistance of externalservicing personnel is required in order to eliminate the fault, acorresponding fault warning is issued to a remote maintenance stationautomatically by the system via a remote control interface of the warewasher. This may be the case, for example, when an insufficient cleaningor final rinse performance of the washing or final rinse system or anincorrect installation of the washing or final rinse arms or a leak inthe line system is the cause of the deviation from the defined watercirculation capacity and from the defined desired pressure,respectively.

The remote maintenance of ware washers is gaining increasing importancein the support of the hardware and software of ware washers. Due to theever greater interlinking of the control devices of ware washers via theInternet, to the set-up of in-house intranets and to conventionaltelecommunication pathways (ISDN, telephone), the possibilities ofdirect support assistance are extended. Not least because of thepossibilities for making savings in travel costs and better resourceutilization (personnel and technology), remote maintenance products areused in order to lower costs in businesses. Remote maintenance programsenable the servicing engineer sitting at a distance to have directaccess to the control device of the ware washer to be maintained and tocarry out corresponding actions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail below with reference to thedrawings in which:

FIG. 1 shows diagrammatically a ware washer, designed in the form of aprogrammable machine, according to a preferred embodiment of theinvention;

FIG. 2 shows diagrammatically a conveyor ware washer according to afurther preferred embodiment of the invention;

FIG. 3 shows diagrammatically the set-up of a washing system for aconveyor ware washer according to the invention or a ware washeraccording to the invention designed as a programmable machine;

FIG. 4 a to f show diagrammatic flow rate profiles to explain theprinciple of the detection of disturbing influences with the aid of theflow rate prevailing in the washing system; and

FIG. 5 a to f show diagrammatic flow rate profiles to explain theprinciple of the detection of disturbing influences with the aid of theflow rate prevailing in the final rinse system.

DETAILED DESCRIPTION

FIG. 1 shows a diagrammatic longitudinal sectional view of an example ofa conveyor ware washer 50. The conveyor ware washer 50 according to theillustration in FIG. 1 has a prewashing zone 51 and a main washing zone52 which is arranged downstream of the prewashing zone 51, as seen inthe direction of transport T of the wash ware (not illustrated in FIG.1). In the conveyor ware washer 50 illustrated in FIG. 1, a postwashingzone 53 and a final rinse zone 54 following the postwashing zone 53 arearranged downstream of the main washing zone 52, as seen in thedirection of transport T. As seen in the direction of transport T,either wash ware received directly on the conveyor belt 58 or wash wareheld by baskets runs in the direction of transport T through an entrytunnel 55, through the following prewashing zone 51, the main washingzone 52, the postwashing zone 53, the final rinse zone 54 and through adrying zone 56 into an exit section 57.

Said treatment zones 51, 52, 53, 54 of the conveyor ware washer 50 areassigned in each case spray nozzles 13-1, 13-2, 13-3, 13-4, via whichliquid is sprayed onto the wash ware which is transported by theconveyor belt 58 through the respective treatment zones 51, 52, 53, 54.At least each washing zone (prewashing zone 51, main washing zone 52,postwashing zone 53) is assigned a tank (washing tank 14-1, 14-2, 14-3),in which sprayed liquid is received and/or in which liquid for the spraynozzles 13-1, 13-2, 13-3 of the respective zones 51, 52, 53 is provided.

The prewashing zone 51, the main washing zone 52 and the postwashingzone 53 of the conveyor ware washer 50 according to the embodimentillustrated in FIG. 1 have in each case a washing system 10-1, 10-2,10-3. Each washing system 10-1, 10-2, 10-3 is composed of a washing pump11-1, 11-2, 11-3, and a line system 12-1, 12-2, 12-3 connected to thewashing pump 11-1, 11-2, 11-3 and of the spray nozzles 13-1, 13-2, 13-3connected to the line system 12-1, 12-2, 12-3.

Further, a control device 20 is provided which serves (inter alia) forsuitably activating the respective washing pumps 11-1, 11-2, 11-3 of thewashing systems 10-1, 10-2, 10-3 during a washing process, in order atleast intermittently to supply liquid via the associated line system12-1, 12-2, 12-3 to the spray nozzles 13-1, 13-2, 13-3 of the nozzlesystem belonging to the respective washing system 10-1, 10-2, 10-3.

In particular, in the conveyor ware washer 50 illustrated in FIG. 1,final rinse liquid in the form of fresh water, which may be mixed withfurther additives, such as, for example, rinsing agent, is sprayed ontothe wash ware, not illustrated in FIG. 1, via the spray nozzles 13-4 ofthe final rinse zone 54 which are arranged above and below the conveyorbelt 58. As illustrated in FIG. 1, laterally arranged spray nozzles 13-5may also be provided in the final rinse zone 54.

Part of the sprayed final rinse liquid is transported from zone to zone,opposite the direction of transport T of the wash ware, via a cascadesystem. The remaining part is conducted directly into the prewashingtank 14-1 via a valve 59 and a bypass line 100.

The sprayed final rinse liquid is captured in the tank (postwashing tank14-3) of the postwashing zone 53, from which tank it is conveyed to thespray nozzles 13-3 (postwashing nozzles) of the postwashing zone 53 viathe washing pump 11-3 belonging to the washing system 10-3 of thepostwashing zone 53. Washing liquid is rinsed off from the wash ware inthe postwashing zone 53. The liquid which in this case occurs flows intothe washing tank 14-2 of the main washing zone 52, is usually providedwith a detergent and is sprayed onto the wash ware, with the aid of awashing pump 11-2 belonging to the washing system 10-2 of the mainwashing zone 52, via the spray nozzles 13-2 (washing nozzles) of thewashing system 10-2 belonging to the main washing zone 52.

The liquid subsequently flows from the washing tank 14-2 of the mainwashing zone 52 into the prewashing tank 14-1 of the prewashing zone 51.The liquid in the prewashing tank 14-1 is sprayed onto the wash ware, bymeans of a washing pump 11-1 belonging to the washing system 10-1 of theprewashing zone 51, via the spray nozzles 13-1 (prewashing nozzles) ofthe washing system 10-1 belonging to the prewashing zone 51, in order tomove coarse impurities from the wash ware.

Each washing system 10-1, 10-2, 10-3 of the conveyor ware washer 50according to FIG. 1 has a sensor device 30 connected to the controldevice 20. The sensor devices 30 serve for detecting a profile of theflow rate of the liquid (washing liquid) which is conveyed to thecorresponding spray nozzles 13-1, 13-2, 13-3 in the respective linesystem 12-1, 12-2, 12-3 of the associated washing system 10-1, 10-2,10-3 with the aid of the associated washing pump 11-1, 11-2, 11-3. Thedetected flow rate profile is subsequently compared with a predetermineddesired flow rate profile which is filed in a storage device 21belonging to the control device 20.

In the conveyor ware washer 50 illustrated in FIG. 1, the control device20 is designed, in the event of a deviation of the detected flow rateprofile from the predetermined flow rate profile either automatically tocarry out, as a function of the size and time gradient of a differencebetween the predetermined flow rate profile and the detected flow rateprofile, a regulating action on the washing process proceeding in therespective treatment zone 51, 52, 53, or to issue a fault warning via anoptical and/or acoustic interface 22 or to issue a fault warning to aremote maintenance station via a remote control interface 23. How thistakes place in particular is stated later with reference to the graphsaccording to FIGS. 4 a to 4 f.

FIG. 2 illustrates a diagrammatic longitudinal sectional view of a warewasher 40 designed in the form of a programmable machine. The warewasher 40 designed as a programmable machine has a treatment chamber 41for the cleaning and final rinse of wash ware, not illustrated in FIG.2. Beneath the treatment chamber 41, a tank 14-4 is arranged, in whichliquid can flow back out of the treatment chamber 41 as a result ofgravity. The tank 14-4 may be covered at the transition to the treatmentchamber 41 with the aid of a screen, not illustrated in FIG. 2.

In the tank 14-4, liquid is located, which is usually water, to which,if appropriate, detergent or rinsing agent can be supplied automaticallyin a controlled way by a detergent or rinsing agent metering device, notillustrated in FIG. 2. The liquid can be conveyed via a line system 12-5to washing nozzles 13-7 by a washing pump 11-5 belonging to a washingsystem 10-4 of the ware washer 40 and can be sprayed through thesewashing nozzles 13-7 in the treatment chamber 41 onto the wash ware tobe cleaned. The sprayed liquid subsequently flows back into the tank14-4. A discharge line 42 with a drain pump 43 may be connected to thelower end of the tank 14-4, in order to empty the tank 14-4, asrequired.

Like the conveyor ware washer 50 illustrated in FIG. 1, the ware washer40 according to FIG. 2, designed as a programmable machine, has,furthermore, a control device 20. This control device 20 serves (interalia) for suitably activating the washing pump 11-5 of the washingsystem 10-4 while the ware washer is in operation, in order at leasttemporarily to supply liquid to the washing nozzles 13-7 via the linesystem 12-5.

Furthermore, the washing system 10-4 of the ware washer 40 according toFIG. 2, designed as a programmable machine, has a sensor device 30connected to the control device 20. As in the conveyor ware washer 50according to the illustration in FIG. 1, the sensor device 30 serves fordetecting a profile of the hydrostatic flow rate of the liquid (washingliquid) which is conveyed to the washing nozzles 13-7 in the line system12-5 of the washing system 10-4 with the aid of the washing pump 11-5.Likewise, in the embodiment according to FIG. 2, the detected flow rateprofile is subsequently compared with a predetermined desired flow rateprofile which is filed in the storage device 21 belonging to the controldevice 20.

In functional terms, the control device 20 provided in the ware washer40 according to FIG. 2, designed as a programmable machine, is identicalto the control device which is used in the conveyor ware washer 50according to FIG. 1. For this reason, there is no need at this juncturefor a detailed description of the functioning of the control device 20.Instead, reference is made in this regard to the following statementsrelating to FIGS. 3 and 4.

It remains to be stated that both the ware washer 40 according to FIG.2, designed as a programmable machine, and the conveyor ware washer 50according to FIG. 1 in each case have at least one washing system, alsodesignated below simply as the “washing system 10”, which comprises anassociated washing pump (also designated below simply as the “washingpump 11”), an associated line system (also designated below simply asthe “line system 12”) connected to the washing pump 11, and alsoassociated washing nozzles (also designated below simply as the “washingnozzles 13”) connected to the line system 12 and integrated in washingarms 15-1 and 15-2. In the ware washer 40 according to FIG. 2, designedas a programmable machine, the washing system 10-4 is based on thewashing pump 11-5, the washing line system 12-5 and the washing nozzles13-7. In the conveyor ware washer 50 according to FIG. 1, at least theprewashing zone 51, the main washing zone 52 and the postwashing zone 53are provided in each case with a corresponding washing system 10-1,10-2, 10-3. These washing systems 10-1, 10-2, 10-3 have in each case awashing pump 11-1, 11-2, 11-3, a line system 12-1, 12-2, 12-3 connectedto the washing pump 11-1, 11-2, 11-3, and spray nozzles 13-1, 13-2, 13-3connected to the line system 12-1, 12-2, 12-3 and designated below as“washing nozzles 13”.

FIG. 3 illustrates a detailed and diagrammatic view of a preferredembodiment of a washing system 10 which may be used, for example, in theconveyor ware washer 50 illustrated in FIG. 1 or in the ware washer 40illustrated in FIG. 2 and designed as a programmable machine.

In the washing system 10 according to FIG. 3, liquid (washing liquid) isrouted in a circuit by a washing pump 11 from a tank 14 via a linesystem 12 to washing nozzles 13 which are installed in upper and lowerwashing arms 15-1, 15-2. In a ware washer (for example, according toFIG. 2) designed as a programmable machine, the washing arms 15-1, 15-2having the washing nozzles 13 are arranged in the treatment chamber 41shown in FIG. 2, so that the washing liquid can be conveyed out of thetank 14 via the line system 12 to the washing nozzles 13 by the washingpump 11 and sprayed through the washing nozzles 13 in the treatmentchamber onto the wash ware to be cleaned (cf. FIG. 2).

In a conveyor ware washer 50 (for example, according to FIG. 1), thewashing system 10 illustrated in FIG. 3 may be provided in at least oneof the respective washing zones (prewashing zone 51, main washing zone52, postwashing zone 53). It is, of course, also conceivable not (only)to use the washing system 10 according to FIG. 3 in one of the washingzones 51, 52, 53, but also in the final rinse zone 54 of the conveyorware washer 50.

Regardless of the question of in which of the respective treatment zonesof a conveyor ware washer the washing system 10 according to theillustration in FIG. 3 is used, in the conveyor ware washer, and also inthe ware washer designed as a programmable machine, the washing liquidis sprayed through the washing tank 14 onto the wash ware via thewashing nozzles 13 with the aid of the washing pump 11.

In contrast to a ware washer 40 (cf. FIG. 2) designed as a programmablemachine, by contrast, in a conveyor ware washer the sprayed washingliquid, after being sprayed, does not, or at least does not completely,flow back into the washing tank 14 of the associated washing system 10.Instead, as already indicated, conveyor ware washers are usuallyequipped with a cascade system, via which at least part of the sprayedwashing liquid is transported from treatment zone to treatment zoneopposite to the direction of transport T of the wash ware. The remainingpart of the sprayed washing liquid may be conducted directly into theprewashing tank 14-1, for example, via a valve 59 and a bypass line 100(cf. FIG. 1).

The washing system 10 illustrated in FIG. 3 has at least one flow sensor31 which belongs to the sensor device 30 already mentioned and which isarranged either at the outlet of the washing pump 11 (cf. ref. 1),upstream of the washing arms 15-1, 15-2 in a line system 12 (cf. ref.2), between two washing arms 15-1, 15-2 in a line system 12 (cf. ref. 3)or in the washing arms 15-1, 15-2 themselves in the immediate vicinityof the washing nozzles 13 (cf. ref. 4 and ref. 5). The at least one flowsensor 31 is designed to detect the profile of the volumetric flow rateQ_(I) in the washing liquid. The flow rate Q_(I) to be detected by theflow sensor 31 is generated in the line system 12 when the washing pump11 is activated during the washing process, in order preferably toensure a virtually constant water circulation capacity.

The washing pump 11 of the washing system 10 illustrated in FIG. 3 isswitched on and off via a control device 20, illustrated in FIG. 1 orFIG. 2, of the ware washer 40, 50 (cf. FIGS. 1 and 2). Furthermore, withthe aid of the control device 20, the rotational speed of the washingpump 11 of the washing system 10 and therefore the water circulationcapacity can advantageously be set.

As already indicated, the at least one flow sensor 31 of the washingsystem 10 belongs to a sensor device 30 which is connected to thecontrol device 20. With the aid of the control device 20, the profile,detected by the flow sensor 31, of the flow rate Q_(I) in the washingliquid is supplied to the control device 20.

FIG. 4 a illustrates in a diagrammatic and idealized way an “ideal”(desired) flow rate profile Q_(S) which is detected by means of thesensor device 30 and which is generated in the washing system 10 duringfault-free operation of the ware washer 40, 50.

The switch-on of the washing pump 11, for example on commencement of thewashing process, takes place at a time point t₀ in the illustrationaccording to FIG. 4 a. The desired flow rate Q_(S) is a volumetric flowrate which is fixed for a selected operating state of the ware washer40, 50 and at which the washing performance required for the operatingstate of the ware washer 40, 50 is achieved.

As illustrated in FIG. 4 a, in fault-free operation of the ware washer40, 50 the flow rate Q_(I) of the washing liquid in the washing system10 has adjusted out after the time t₁ at the desired flow rate Q_(S)fixed for the set treatment program. If the flow rate detected by meansof the at least one flow sensor 31 of the sensor device 30 does notdeviate from the desired flow rate Q_(S) over a time interval Δt₁, thenthere are no machine-side problems.

The (first) time interval Δt₁ serves, in the embodiment illustrated inFIG. 4, as a time window for determining whether a fault-free operationof the ware washer 40, 50 is present or not. Within the first timeinterval Δt₁, the flow rate Q_(I) in the washing system 10 is measuredcontinuously with the aid of the at least one flow sensor 31. It is alsoconceivable, however, that, within the time interval Δt₁, thehydrostatic flow rate Q_(I) is measured by predetermined time points orevents, and the measured flow rate values are subsequently interpolated,in order to obtain a profile of the flow rate in the time interval Δt₁.

Preferably, the time interval Δt₁ has a set length, which may be apredetermined or predeterminable (e.g., manufacturer, service person oroperator programmable or settable) length, the start of the timeinterval Δt₁ being fixed by a time point t₁ at which the washing pump 11is switched on or activated during the washing process in such a waythat the washing liquid is supplied to the at least one washing nozzle13 via the line system 12. As illustrated in FIG. 4 a, the start of thetime interval Δt₁ lies at a time point t₁ directly after the expiry ofan adjustment time of the flow rate Q_(I) generated in the line system12 after the switch-on of the washing pump 11. However, it is, ofcourse, also conceivable to select the start of the time interval Δt₁ atanother time point.

The ideal flow rate Q_(S) to be expected in fault-free operation of theware washer 40, 50 is filed in the control device 20 of the ware washer40, 50, specifically preferably for each treatment program of the warewasher 40, 50, if different treatment programs are provided for this andif different water circulation capacities and desired flow rates arerequired for the washing processes of the respective treatment programs,respectively. It is, of course, also conceivable, however, that theideal flow rate profiles Q_(S) to be expected in fault-free operation ofthe ware washer are not filed in the control device 20 itself, but in astorage device 21 connected to the control device 20, in which case thecontrol device 20 can have access to the storage device 21, as required,in order to read out the flow rate profile Q_(S) ideal for the washingprocess to be carried out.

The ideal flow rate profile Q_(S) in the washing system 10 which is tobe expected in fault-free operation of the ware washer 40, 50 ispreferably filed previously in the control device 20 or storage device21. It is, of course, also conceivable, however, that the ideal flowrate profile Q_(S) is a flow rate profile which has been detected by thesensor device 30 during an earlier washing process and filed in thecontrol device 20 or in the storage device 21. The advantage of thisalternative is that, with the aid of the solution according to theinvention, it is possible to detect whether or not a particularly slowlyoccurring deviation of the detected flow rate profile arises in thecourse of time, as seen over a plurality of washing processes, and thismay serve as an indicator of, for example, the degree of contaminationof the washing nozzles 13 or as an indicator of the degree ofcontamination of a filter device provided, if appropriate, in thewashing system.

After the flow rate profile Q_(I) detected over the time interval Δt₁ bythe sensor device 30 has been supplied to the control device 20, acomparison takes place between the detected flow rate profile Q_(I) andthe ideal flow rate profile Q_(S) which is filed, for example, in thecontrol device 20 and which is to be expected in fault-free operation ofthe ware washer 40, 50. If a deviation of the detected flow rate profileQ_(I) from the expected flow rate profile Q_(S) arises, an analysis ofthe deviation takes place automatically in order to determine the causeof this and to bring about appropriate countermeasures.

It must be remembered, in this case, that, in determining whether adeviation from the ideal flow rate profile Q_(S) is present or not, acertain deviation range has to be taken into account. Preferably, inthis case, the control device 20 should be designed in such a way thatit finds a deviation from the ideal flow rate profile Q_(S) andtherefore an operation of the ware washer 40, 50 which is notfault-free, only when the deviation of the detected flow rate profileQ_(I) from the predetermined flow rate profile Q_(S) overshoots orundershoots a predetermined or predeterminable (e.g., manufacturer,service person or operator programmable or settable) threshold value S₀.

It is, of course, also conceivable that the flow rate profile Q_(I)detected by the sensor device 30 is averaged, filtered, smoothed orotherwise processed before comparison with the predetermined (ideal)flow rate profile Q_(S).

In the evaluation of the detected flow rate profile Q_(I), andparticularly in the comparison of the detected (and, if appropriate,processed) flow rate profile Q_(I) with the predetermined ideal flowrate profile Q_(S), it is determined whether a deviation from the idealflow rate profile Q_(S) is present or not. However, the presentinvention is not restricted only to ascertaining the deviation from theideal flow rate profile Q_(S); on the contrary, according to theinvention, there is provision, in the presence of a deviation of thedetected flow rate profile Q_(I) from the predetermined flow rateprofile Q_(S), for evaluating the type of deviation so that a conclusionas to the disturbing influence responsible for this deviation can bedrawn. In the embodiment illustrated, the type of deviation of thedetected flow rate profile Q_(I) from the ideal flow rate profile Q_(S)is to be understood as being, in particular, the size and time gradientof a difference between the predetermined flow rate profile Q_(S) (asminuend) and the detected flow rate profile Q_(I) (as subtrahend). Inparticular, not only is the amount of the deviation relevant, but alsothe question as to whether the detected flow rate Q_(I) is higher thanor lower than the predetermined flow rate Q_(S), and how the timebehaviour of the flow rate profile Q_(I) appears.

It is described in detail below, with reference to the illustrationsaccording to FIGS. 4 a to 4 f, how, in a preferred embodiment of theinvention, a conclusion can be drawn as to different disturbinginfluences on the basis of the type of deviation of the detected flowrate profile Q_(I) from the ideal flow rate profile Q_(S) illustrated,for example, in FIG. 4 a. In this case, FIGS. 4 a to 4 f illustrate in adiagrammatic and idealized way flow rate profiles which have beendetected with the aid of the sensor device 30 in a preferred embodimentof the invention.

In this case, it must be remembered that, in the illustrations accordingto FIGS. 4 b to 4 d, the time interval Δt₁ (first time interval Δt₁)serves as a time window for detecting the actual flow rate profileQ_(I). In the case of the flow rate profiles Q_(I) illustrated, thefirst time interval Δt₁ commences at the time point t₁ immediately afterthe expiry of an adjustment time of the flow rate generated in the linesystem 12 by the washing pump 11 being switched on. The end of the firsttime interval Δt₁ is defined by the time point t₂. The time point t₂ ispreferably selected in such a way that a sufficient number of flow ratemeasurements can be carried out in the first time interval Δt₁ so thatreliable evidence of the flow rate Q_(I) actually prevailing in thewashing system 10 can be obtained. The time point t₂ depends, inparticular, on the sensing rate achievable by the sensor device 30 orthe at least one flow sensor 31 and on the accuracy desired for thedetected flow rate profile Q_(I).

As already indicated, the graph according to FIG. 4 a illustrates theflow rate profile Q_(S), such as can be expected in fault-free operationof the washing system 10. This flow arte profile Q_(S) constitutes theideal or predetermined flow rate profile. A deviation from this ariseswhen a fault occurs during operation, that is to say during the washingphase in the washing system 10. In the graphs according to FIGS. 4 b to4 f, the ideal desired flow rate profile Q_(S) is illustrated once againas a dashed curve profile for clearer understanding.

The basic flow rate profile Q_(I) illustrated in the graph according toFIG. 4 b is a flow rate profile which is detected with the aid of thesensor device 30 when a minor leak is present in the washing system 10.As illustrated, in the time window (first time interval Δt₁) taken intoaccount, the detected flow rate Q_(I) in the washing system 10 liesslightly above the desired flow rate Q_(S). In the instance illustratedin FIG. 4 b, that is to say when the detected flow rate profile Q_(I)lies continuously below the predetermined flow rate profile within thetime window (first time interval Δt₁) to be taken into account, and whenthe amount of the difference between the predetermined flow rate profileQ_(S) and the detected flow rate profile Q_(I) lies continuously withina range between a first fixed threshold value S₁ and a second fixedthreshold value S₂, a minor leak in the washing system 10 is concludedautomatically with the aid of the control device 20. In this case, acorresponding fault warning is generated automatically by the controldevice 20 and is issued via the optical and/or acoustic interface 22 ofthe ware washer 40, 50, in order to draw the attention of the operatorof the ware washer 40, 50 to the (minor) leak in the washing system 10.

Alternatively or additionally to this, it is conceivable that thecontrol device 20 also automatically generates a corresponding faultwarning and communicates this directly to a remote maintenance station(remote maintenance service) via the remote control interface 23 of theware washer 40, 50.

As a reaction to the fault warning issued via the optical/acousticinterface 22 and/or via the remote control interface 23, appropriatemeasures can then be introduced by the ware washer operator or theremote maintenance station in order to compensate the effect of thedetected leak on the washing performance of the ware washer 40, 50.

The graph according to the illustration in FIG. 4 c is a basic flow rateprofile Q_(I) which occurs in the event of a major leak in the washingsystem 10 or in the event of incorrect or neglected installation of thewashing arms 15-1, 15-2 or in the event of an absence of washing armcleaning caps. As illustrated in FIG. 4 c, during the time window (firsttime interval Δt₁) to be taken into account, only a relatively high flowrate is generated in the washing system 10, which lies below the secondthreshold value S₂ and well above the desired flow rate Q_(S) and doesnot approach the desired flow rate Q_(S) over the time interval Δt₁.

In this case, that is to say when the detected flow rate value liescontinuously above the predetermined flow rate profile Q_(S) and theamount of the difference between the predetermined flow rate profileQ_(S) and the detected flow rate profile Q_(I) is continuously greaterthan the second fixed threshold value S₂, a major leak in the washingsystem 10 is concluded automatically by the control device 20 and acorresponding fault warning is issued preferably via the optical and/oracoustic interface 22 of the ware washer 40, 50 in order to draw theattention of the operator of the ware washer 40, 50 to a major leak inthe washing system 10.

So that a differentiation can be made as to whether the washing flowrate deviation in the washing system detected in the scenario accordingto FIG. 4 c is the result of a leak or the result of an incorrectinstallation of at least one of the washing arms 15-1, 15-2 or theresult of the absence of washing arm cleaning caps, it is basicallyconceivable to provide suitable washing arm position sensors, via whichcorresponding warnings are issued if at least one of the washing arms15-1, 15-2 is installed incorrectly or if washing arm cleaning caps areabsent. In this development, a major leak in the washing system 10 ispresent when the detected flow rate profile Q_(I) lies continuouslyabove the predetermined flow rate profile Q_(S) within the first timeinterval Δt_(I) and the amount of the difference between thepredetermined flow rate profile Q_(S) and the detected flow rate profileQ_(I) is continuously greater than the second fixed threshold value S₂,and when the washing arm position sensors issue no fault warning.

The graph according to the illustration in FIG. 4 d shows in adiagrammatic and idealized way the basic flow rate profile Q_(I) whichis established in the washing system 10 when one or more clogged washingnozzles 13 are present. As illustrated in FIG. 4 d, in the event of sucha fault the flow rate Q_(I) in the washing system 10 lies continuouslybelow the desired flow rate Q_(S) during the time window Δt_(I) to betaken into account.

In this case, that is to say when the detected flow rate profile Q_(I)lies continuously below the predetermined flow rate profile Q_(S) andthe amount of the difference between the predetermined flow rate profileQ_(S) and the detected flow rate profile Q_(I) is continuously greaterthan a fixed threshold value S₀ characteristic of the presence of adeviation, the presence of a blockage in the washing system 10 isconcluded automatically by the control device 20. Consequently, acorresponding fault warning is issued automatically, preferably via theoptical and/or acoustic interface 22, in order to indicate to theoperator of the ware washer 40, 50 that, for example, at least onewashing nozzle 13 has to be cleaned.

It is conceivable in this case, that evidence as to the degree ofblockage or the number of nozzles to be cleaned can also be obtained bymeans of the amount of the deviation of the detected flow rate profileQ_(I) from the predetermined flow rate profile Q_(S).

The invention is not restricted only to evaluating the detected (actual)flow rate profile Q_(I) in the washing system 10 by means of apredetermined (ideal) flow rate profile Q_(S) at the commencement of thewashing process, that is to say within the first time interval Δt_(I),so that conclusions as to possible disturbing influences can be drawn.On the contrary, the solution according to the invention also covers thedetection and evaluation of the actual flow rate profile Q_(I) during asecond time interval Δt₂. The second time interval Δt₂ may lie in anydesired range during the washing process.

In the illustrations according to 4 a to 4 f, therefore, the flow rateprofile Q_(I) is not only evaluated in the first time interval Δt₁,which preferably lies immediately after the expiry of the adjustmenttime of the flow rate generated in the line system 12 by the washingpump 11 being switched on, but also in the second time interval Δt₂,wherein in the graphs illustrated this second time interval Δt₂commences at the end of the first time interval Δt₁ (at the time pointt₂) and preferably lasts as long as the washing pump 11 is running.

Possible flow rate profiles, from which disturbances or faults occurringduring the washing process become clear, are dealt with below withreference to the graphs according to the illustrations in FIGS. 4 e and4 f.

The graph according to the illustration in FIG. 4 e is a basic flow rateprofile Q_(I) in the event of leakage occurring during the washingprocess. The graph shows that no faults have occurred during the firsttime interval Δt₁. In the second time interval Δt₂, the start of whichis defined by the time point t₂ (end point of the first time intervalΔt₁), the detected flow rate Q_(I) in the washing system 10 fallscontinuously at the time point t₃. In this case, that is to say when themeasured flow rate Q_(I) falls continuously within the second timeinterval Δt₂ from a time point t₃ lying in the time window Δt₂, theoccurrence of a leakage in the washing system 10 is concludedautomatically, preferably after an upper threshold value is overshot.

The graph according to the illustration in FIG. 4 f shows the basic flowrate profile Q_(I) which is established when a blockage occurs in thewashing system 10 during continuous washing operation (that is to say,within the second time interval Δt₂). This is the case, for example,when individual washing nozzles 13 become at least partially blockedduring the continuous operation of the ware washer 40, 50. In this case,that is to say when the measured hydrostatic flow rate Q_(I) decreasescontinuously from a time point t₃ during the second time interval Δt₂ orduring the continuous operation of the ware washer 40, 50, a blockage ofthe washing system 10 occurring only during the continuous operation ofthe ware washer 40, 50 is concluded automatically. Consequently, acorresponding fault warning is issued automatically, preferably via theoptical and/or acoustic interface 22, in order to draw the attention ofthe operator of the ware washer 40, 50 to this disturbing factor.

In a case when, within a time interval Δt₁, Δt₂ during which the flowrate profile is detected, the measured volumetric flow rate Q_(I) isreduced due to a blockage in the washing system 10 (cf. FIGS. 4 d and 4f), the process can be affected as follows: in a ware washer 40 designedas a programmable machine, the running time of the treatment programshall be increased, preferably in proportion to the detected flow ratedrop. On the other hand, however, in a ware washer 50 designed as aconveyor ware washer, the speed at which the washing items to be treatedare transported through the ware washer 50 shall be decreased preferablyin proportion to the detected flow rate drop thereby increasing thetreatment time of the washing items in the conveyor ware washer.

In the above-described embodiment of the solution according to theinvention, a ware washer 40, 50 is assumed which has at least onewashing pump (washing pumps 11-1, 11-2, 11-3 in the conveyor ware washer50 shown in FIG. 1 and washing pump 11-5 in the ware washer 40 shown inFIG. 2 and designed as a programmable machine) and at least one washingnozzle 13-1, 13-2, 13-3, 13-7 which is connected to the washing pump11-1, 11-2, 11-3, 11-5 via a line system 12-1, 12-2, 12-3, 12-5 and towhich a washing liquid is supplied during a washing process by thewashing pump 11-1, 11-2, 11-3, 11-5 being activated, during the washingprocess the profile Q_(I) of the flow rate of the washing liquid in theline system 12-1, 12-2, 12-3, 12-5 being detected and being comparedwith a predetermined flow rate profile Q_(S).

Alternatively or additionally to this, however, it is also conceivable,during a final rinse process, to detect the profile Q_(I) of the flowrate of the final rinse liquid supplied to the nozzles 13-4, 13-5, 13-6provided for final rinse and to compare it with a predetermined flowrate profile Q_(S).

In this case, it must be remembered that the conveyor ware washer 50illustrated, for example, in FIG. 1 has a final rinse pump 11-4 andfinal rinse nozzles 13-4, 13-5 connected to the final rinse pump 11-4via the line system 12-4. During a final rinse process, final rinseliquid is supplied to the final rinse nozzles 13-4, 13-5 by the finalrinse pump 11-4 being activated. In order to achieve a situation where,during the final rinse process, the profile Q_(I) of the flow rate ofthe final rinse liquid in the line system 12-4 can be detected andcompared with a predetermined flow rate profile Q_(S), in the conveyorware washer 50 illustrated in FIG. 1 a sensor device 30′ is provided,having at least one pressure sensor 31′ which may be arranged, forexample, at the outlet of the final rinse pump 11-4 or in the linesystem 12-4 in the immediate vicinity of the final rinse nozzles 13-4,13-5. The at least one pressure sensor 31′ is designed to detect theprofile of the volumetric flow rate Q_(I) in the final rinse liquid. Theflow rate Q_(I) to be detected by the flow sensor 31′ is generated inthe line system 12-4 when the final rinse pump 11-4 is activated duringthe final rinse process.

The final rinse pump 11-4 of the conveyor ware washer 50 illustrated inFIG. 1 is switched on and off via the control device 20 of the warewasher 50. Furthermore, with the aid of the control device 20, therotational speed of the final rinse pump 11-4 and therefore the quantityof final rinse liquid supplied per unit time for the final rinse nozzles13-4, 13-5 can advantageously be set.

On the other hand, it is, of course, also conceivable, in the warewasher 40 illustrated in FIG. 2 and designed as a programmable machine,during a final rinse process to detect the profile Q_(I) of the flowrate of the final rinse liquid supplied to the final rinse nozzles 13-6provided for final rinse and to compare it with a predetermined flowrate profile Q_(S). In this case, it must be remembered that, in theembodiment, illustrated in FIG. 2, of the ware washer 40 designed as aprogrammable machine, a final rinse pump 11-6 is provided which isconnected with its suction side to an outlet of a water heater (boiler)60. The water heater 60 has an inlet connected to a fresh water supplyline 61. The fresh water supply line 61 is connectable to further freshwater supply lines 63, 64 via a valve 62, so that either fresh water orfresh water with added rinse agent can be supplied to the water heater60. The water heater 60 has a heating system, so that the liquid (purefresh water or fresh water with added rinse agent) supplied via theinlet can be heated in accordance with a process flow.

Via the final rinse pump 11-6 connected with its suction side to theoutlet of the water heater 60, the final rinse liquid optionally heatedin the water heater 60 or unheated can be routed, for example during afinal rinse phase, to the final rinse nozzles 13-6 via a final rinseline system 12-6. The final rinse nozzles 13-6 are arranged in thetreatment chamber 41, in order to spray the final rinse liquid heated inthe water heater 60 onto the wash ware in the treatment chamber 41. Itis, of course, also conceivable, however, that the water heater 60 issupplied with pure fresh water, to which a rinse agent is added onlyafter heating in the water heater 60.

The solution according to the invention is not restricted to thepresence of a water heater 60. On the contrary, within the scope of theinvention, the provision of a water heater 60 may even be dispensedwith, so that, during a final rinse process, unheated final rinse liquidis conveyed to the final rinse nozzles 13-6 arranged in the treatmentchamber 41 and is sprayed onto the wash ware.

In the embodiment, illustrated diagrammatically in FIG. 2, of the warewasher 40 designed as a programmable machine, the washing nozzles 13-7and the final rinse nozzles 13-6 are in each case preferably arrangedabove and below the wash ware region and are directed toward the washware region of the treatment chamber 41. In particular, in theembodiment illustrated, a downwardly directed upper washing nozzlesystem and a likewise downwardly directed upper final rinse nozzlesystem, formed separately from this, and also an upwardly directed lowerwashing nozzle system and a likewise upwardly directed lower final rinsenozzle system, formed separately from this, are provided. It is, ofcourse, also conceivable, however, to provide an upper and a lowerwashing nozzle system which serve jointly for the spraying of washingliquid (during a washing phase) and for the spraying of final rinseliquid (during a final rinse phase). Also, the washing nozzles 13-7and/or the final rinse nozzles 13-6 may be arranged only at the top oronly at the bottom, instead of at the bottom and top, or, instead oradditionally, may also be arranged on one side of the treatment chamber41 and be directed into the wash ware region transversely with respectto the treatment chamber 41.

During a final rinse process, in the embodiment, illustrateddiagrammatically in FIG. 2, of the ware washer 40 designed as aprogrammable machine, final rinse liquid is supplied to the final rinsenozzles 13-6 by the final rinse pump 11-6 being activated. In order toachieve the situation where, during the final rinse process, the profileQ_(I) of the flow rate of the final rinse liquid in the line system 12-6can be detected and compared with a predetermined flow rate profileQ_(S), in the ware washer 40 illustrated in FIG. 2 a sensor device 30″is provided, having at least one flow sensor 31″ which may be arranged,for example, at the outlet of the final rinse pump 11-6 or in the linesystem 12-6 between the final rinse pump 11-6 and the final rinsenozzles 13-6. The at least one flow sensor 31″ is designed to detect theprofile of the hydrostatic flow rate Q_(I) in the final rinse liquid.The flow rate Q_(I) to be detected by the flow sensor 31″ is generatedin the line system 12-6 when the final rinse pump 11-6 is activatedduring the final rinse process.

The final rinse pump 11-6 of the ware washer 40 illustrated in FIG. 2 isswitched on and off via the control device 20 of the ware washer 40.Furthermore, with the aid of the control device 20, the rotational speedof the final rinse pump 11-6 and therefore the quantity of final rinseliquid supplied per unit time to the final rinse nozzles 13-6 canadvantageously be set.

FIGS. 5 a to 5 f illustrate flow rate profiles which were recorded, inthe conveyor ware washer according to FIG. 1, with the aid of the sensordevice 30′ or, in the ware washer 40 designed as a programmable machine,with the aid of the sensor device 30″ and which correspond respectivelyto the flow rate profile of the volumetric flow rate of the final rinseliquid in the line system 12-4 and to the flow rate profile of thevolumetric flow rate of the final rinse liquid in the line system 12-6during a final rinse process. The flow rate profiles illustrated inFIGS. 5 a to 5 f for the final rinse system largely correspond inprofile and indication to the flow rate profiles in the washing systemwhich are explained in FIGS. 4 a to 4 f. The observations explainedthere for the washing system may be transferred similarly to the finalrinse system, and in this case the flow rate profiles of the liquids inthe washing system may differ from those in the final rinse system,where appropriate, in their amplitudes (desired flow rate Q_(S),detected flow rate Q_(I), threshold values S₀, S₁, S₂).

The invention is not restricted to the embodiments shown by way ofexample in the drawings. On the contrary, the invention may be gatheredfrom an overall consideration by a person skilled in the art of thepatent claims and of the description of the exemplary embodiments.

Thus, it is, of course, conceivable that the start of the second timeinterval Δt₂ illustrated in FIGS. 4 a to 4 f does not coincide with theend (time point t₂) of the first time interval Δt₁. In particular, it isconceivable that the second time interval Δt₂, like the first timeinterval Δt₁, commences even immediately after the expiry of thesettling time of the flow rate which is generated in the washing system10 when the washing pump 11 is switched on.

On the other hand, it is nevertheless conceivable that the profile ofthe flow rate Q_(I) is detected with the aid of the sensor device 30,30′, 30″, in that the flow rate is measured continuously during theentire washing and/or final rinse process, or in that the flow rate ismeasured at predetermined or predeterminable time points or eventsduring the entire washing and/or final rinse process, and the measuredflow rate values are interpolated.

The solution according to the invention makes it possible automaticallyto ascertain and evaluate a deviation of the flow rate profile Q_(I)prevailing in the washing system and/or final rinse system from an idealprefixed flow rate profile Q_(S), in order to record disturbances orfaults which are responsible for the flow rate deviation and whicheither are present even at the commencement of the washing process orfirst arise during the washing or final rinse process. Suitable measuresare taken automatically as a function of the type of disturbance, inorder either to maintain the desired washing performance of the warewasher or, if this is not possible, to maintain the operation of theware washer, without entailing the risk of damage occurring on the warewasher.

1. A method for operating a ware washer which is designed as aprogrammable machine or as a conveyor ware washer having at least onepump, at least one line system connected to the pump, and at least onenozzle system connected to the line system and having at least onenozzle, the method having the following method steps: during theoperation of the ware washer, a liquid is supplied at leastintermittently to the at least one nozzle via the line system; and theprofile of the flow rate of the liquid in the line system is detectedand is compared with a predetermined flow rate profile, characterized,in that, in the event of a deviation of the detected flow rate profilefrom the predetermined flow rate profile, at least one of the followingsteps is selected and executed automatically as a function of the sizeand the time gradient of a difference between the predetermined flowrate profile and the detected flow rate profile: i) regulating action iscarried out on the operation of the ware washer; and/or ii) a faultwarning is issued via an optical and/or acoustic interface of the warewasher; and/or iii) a warning is issued to a remote maintenance stationvia a remote control interface of the ware washer.
 2. The method asclaimed in claim 1, wherein the at least one pump is has a washing pumpand the at least one nozzle is a washing nozzle which is connected tothe washing pump via the line system and to which a washing liquid issupplied during a washing process via the washing pump being activated,and wherein, during the washing process, the profile of the volumetricflow rate of the washing liquid in the line system is detected andcompared with the predetermined flow rate profile.
 3. The method asclaimed in claim 2, wherein the ware washer has a final rinse pump andat least one final rinse nozzle which is connected to the final rinsepump via a final rinse line system and to which a final rinse liquid issupplied during a final rinse process by the final rinse pump beingactivated, and wherein, during a final rinse process, the profile of thevolumetric flow rate of the final rinse liquid in the final rinse linesystem is detected and compared with the a predetermined final rinseflow rate profile.
 4. The method as claimed in claim 2, wherein the warewasher has a valve and at least one final rinse nozzle which isconnected to the valve via a final rinse line system and to which afinal rinse liquid is supplied during the final rinse process by thevalve being opened, and wherein, during the final rinse process, theprofile of the volumetric flow rate of the final rinse liquid in thefinal rinse line system is detected and compared with a predeterminedfinal rinse flow rate profile.
 5. The method as claimed in claim 1,wherein at least one of the steps i) to iii) is selected and executedautomatically only when the deviation of the detected flow rate profilefrom the predetermined flow rate profile overshoots or undershoots a setthreshold value.
 6. The method as claimed in claim 1, wherein theprofile of the volumetric flow rate is detected in that the volumetricflow rate is measured continuously within at least one predeterminedtime interval, or in that the volumetric flow rate is measured atpredetermined time points or events within at least one predeterminedtime interval, and the measured flow rate values are interpolated. 7.The method as claimed in claim 6, wherein the time interval has a setlength, and wherein the start of the time interval is fixed by a timepoint at which the pump is switched on or activated in such a way thatthe liquid is supplied via the line system to the nozzle system havingthe at least one nozzle.
 8. The method as claimed in claim 7, whereinthe profile of the volumetric flow rate is detected in that thevolumetric flow rate is measured continuously or at predetermined timepoints or events in a plurality of time intervals preferably directlycontiguous to one another, the start of the first time interval lying ata time point preferably immediately after the expiry of a starting timeof the flow rate generated in the line system by the pump being switchedon.
 9. The method as claimed in claim 1, wherein, in a case when thedetected flow rate profile lies continuously above the predeterminedflow rate profile and the amount of the difference between thepredetermined flow rate profile and the detected flow rate profile liescontinuously within the range between a first fixed threshold value anda second fixed threshold value, a minor leak in the line system ornozzle system is concluded automatically, and wherein a correspondingfault warning then is issued via the optical and/or acoustic interface;and/or wherein a corresponding fault warning then is issued via theremote control interface.
 10. The method as claimed in claim 9, wherein,in a case when the detected flow rate profile lies continuously abovethe predetermined flow rate profile and the amount of the differencebetween the predetermined flow rate profile and the detected flow rateprofile is continuously above the second fixed threshold value, a majorleak in the line system or nozzle system is concluded automatically, anda corresponding fault warning is issued via the optical and/or acousticinterface.
 11. The method as claimed in claim 1, wherein, in a case whenthe detected flow rate profile lies continuously below the predeterminedflow rate profile and the amount of the difference between thepredetermined flow rate profile and the detected flow rate profile iscontinuously above a fixed threshold value, a blockage in the linesystem or nozzle system is concluded automatically, and a correspondingfault warning is issued via the optical and/or acoustic interface. 12.The method as claimed in claim 11, wherein the at least one pump is hasa washing pump and the at least one nozzle is a washing nozzle which isconnected to the washing pump via the line system and to which a washingliquid is supplied during a washing process by the washing pump beingactivated, and wherein, during the washing process, the profile of thevolumetric flow rate of the washing liquid in the line system isdetected and compared with the predetermined flow rate profile.
 13. Themethod as claimed in claim 12, wherein, if the ware washer is designedas a programmable machine, the running time of the treatment program isincreased, preferably in proportion to the detected flow rate drop; orwherein, if the ware washer is designed as a conveyor ware washer, thespeed at which the washing items to be treated are transported throughthe ware washer is reduced preferably in proportion to the detected flowrate drop.
 14. The method as claimed in claim 1, wherein, in a casewhen, within a time interval during which the flow rate profile isdetected, the measured volumetric flow rate increases continuously froma time point and overshoots a predetermined threshold value, the pumpcapacity of the pump is automatically adjusted down, preferably ininverse proportion to a detected flow rate rise.
 15. The method asclaimed in one of claim 1, wherein, in a case when, within a timeinterval during which the flow rate profile is detected, the measuredvolumetric flow rate decreases continuously from a time point andundershoots a predetermined threshold value, a blockage occurring onlyduring the continuous operation of the ware washer is concludedautomatically, and a corresponding fault warning is issued via theoptical and/or acoustic interface.
 16. A ware washer, in particularcommercial dishwasher or utensil ware washer, which is designed as aprogrammable machine or as a conveyor ware washer and has the following:at least one pump; at least one line system connected to the pump; atleast one nozzle system connected to the line system and having at leastone nozzle, a liquid being supplied at least intermittently to the atleast one nozzle via the line system; and a sensor device connected to acontrol device, for detecting a profile of the volumetric flow rate ofthe liquid in the line system and for comparing the detected flow rateprofile with a predetermined flow rate profile, characterized, in thatthe control device is designed, in the event of a deviation of thedetected flow rate profile from the predetermined flow rate profile,automatically either to carry out a regulating action on the operationof the ware washer as a function of the size and the time gradient of adifference between the predetermined flow rate profile and the detectedflow rate profile or to issue a fault warning via an optical and/oracoustic interface or to issue a fault warning to a remote maintenancestation via a remote control interface.
 17. The ware washer as claimedin claim 16, wherein the ware washer has, furthermore, the following: atleast one valve; at least one final rinse line system connected to thevalve; and at least one nozzle system connected to the line system andhaving at least one final rinse nozzle, wherein the control device isdesigned, furthermore, for activating the valve in such a way that aliquid is supplied at least intermittently to the at least one finalrinse nozzle via the final rinse line system, and wherein the sensordevice is designed, furthermore, for detecting a profile of thevolumetric flow rate of the liquid in the final rinse line system andfor comparing the detected flow rate profile with a predetermined finalrinse flow rate profile.
 18. The ware washer as claimed in claim 16,wherein the control device is designed, furthermore, to carry out aregulating action on the operation of the ware washer or to issue afault warning only when the deviation of the detected flow rate profilefrom the predetermined flow rate profile overshoots or undershoots a setthreshold value.
 19. The ware washer as claimed in claim 16, wherein thesensor device has at least one flow sensor, and is designed to detectthe profile of the volumetric flow rate in that the volumetric flow rateis measured continuously or at predetermined time points or events bymeans of the at least one flow sensor within a predetermined timeinterval, and, if appropriate, the measured flow rate values areinterpolated.
 20. The ware washer as claimed in claim 16, wherein the atleast one pump is ware washer has a washing pump and the at least onenozzle is a washing nozzle which is connected to the washing pump viathe line system and to which a washing liquid is supplied during awashing process by the washing pump being activated, and wherein thesensor device connected to the control device is designed for detectingthe profile of the volumetric flow rate of the washing liquid in theline system and for comparing the detected flow rate profile with thepredetermined flow rate profile.
 21. The ware washer as claimed in claim16, wherein the at least one pump is ware washer has a final rinse pumpand the at least one nozzle is a final rinse nozzle which is connectedto the final rinse pump via the line system and to which a final rinseliquid is supplied during a final rinse process by the final rinse pumpbeing activated, and wherein the sensor device connected to the controldevice is designed for detecting the profile of the volumetric flow rateof the final rinse liquid in the line system and for comparing thedetected flow rate profile with the predetermined flow rate profile.